Gear pumps use meshed gears to pump fluid by displacement. Gear pumps exhibit positive or fixed displacement performance, meaning they pump a predetermined amount of fluid for each revolution. As the gears rotate they separate on an intake side of the pump, creating a void that is filled by the fluid being pumped. The fluid is carried in the spaces between the gear teeth about the outer peripheries of the gears to a discharge side of the pump. As the gears mesh, the fluid is displaced and flows out the discharge side of the pump. The intermeshing of the gears, along with the speed of rotation of the gears, effectively prevents leakage and backflow of the fluid being pumped.
Cavitation is a term that is used to describe a phenomenon in which bubbles or “vapor cavities” can form in a fluid due to forces acting upon the fluid. Cavitation can be caused by rapidly dropping the pressure of a fluid. When subjected to higher pressure, the bubbles can implode, generating intense shockwaves. These shockwaves can cause wear in some mechanical devices. Vapor cavities that implode near solid surfaces can cause cyclic stresses through repeated exposure to such implosions. Repeated exposure can lead to surface fatigue of the solid surface and can cause a type of wear also referred to as “cavitation”. This type of wear can occur upon solid surfaces such as pump impellers, generally at locations where sudden changes in the pressures of liquids occur.